From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B224CC433DF for ; Wed, 10 Jun 2020 20:14:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 727672074B for ; Wed, 10 Jun 2020 20:14:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Ib0/cbiZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 727672074B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6D7528D000D; Wed, 10 Jun 2020 16:13:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 686568D0009; Wed, 10 Jun 2020 16:13:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 526948D000D; Wed, 10 Jun 2020 16:13:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0084.hostedemail.com [216.40.44.84]) by kanga.kvack.org (Postfix) with ESMTP id 34AEE8D000C for ; Wed, 10 Jun 2020 16:13:51 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id DF876181ABEA4 for ; Wed, 10 Jun 2020 20:13:50 +0000 (UTC) X-FDA: 76914403020.21.crook55_111447c26dce Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id B6690180442ED for ; Wed, 10 Jun 2020 20:13:50 +0000 (UTC) X-HE-Tag: crook55_111447c26dce X-Filterd-Recvd-Size: 3501 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Wed, 10 Jun 2020 20:13:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=WueiR9ClBR+SuUmlwhBVixkLUapU9LiFVjs2FwKptFw=; b=Ib0/cbiZsMjrh5GZh4ZA8ZsdY2 klpGZJeArXDdQfA2xiQwLfZNtsV95uw+Q/RHNtGh8hpAOnotLkrSmMge24xAWMgPIZL9d6YQhdPIF P05camGYRlTJ1tZNEhJ4tv4nbwD86PMeP30wQ5SAxEZrgJSK68d9usY7lJFV1jiUEYpMen39soRQ4 yR7pcyiXFKgjgoumY2NiTcWzA/WgduKS2tg0ud4bV5A3+m9xmSoC66ciYwGftMtfGfx35qtwXGOSN 69rSoh0QIvooYftJKD2LAW91mhgPhd9WJGlRvA8pfxm/loFcLgvSh23dHahH1GVXhnmmrSZJHqY6C nPY9qiUA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jj76Z-0003Up-Vj; Wed, 10 Jun 2020 20:13:47 +0000 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 19/51] mm: Zero the head page, not the tail page Date: Wed, 10 Jun 2020 13:13:13 -0700 Message-Id: <20200610201345.13273-20-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200610201345.13273-1-willy@infradead.org> References: <20200610201345.13273-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Queue-Id: B6690180442ED X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: "Matthew Wilcox (Oracle)" Pass the head page to zero_user_segment(), not the tail page, and adjust the byte offsets appropriately. Signed-off-by: Matthew Wilcox (Oracle) --- mm/shmem.c | 7 +++++++ mm/truncate.c | 7 +++++++ 2 files changed, 14 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index a05d129a45e9..55405d811cfd 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -898,11 +898,18 @@ static void shmem_undo_range(struct inode *inode, l= off_t lstart, loff_t lend, struct page *page =3D NULL; shmem_getpage(inode, start - 1, &page, SGP_READ); if (page) { + struct page *head =3D thp_head(page); unsigned int top =3D PAGE_SIZE; if (start > end) { top =3D partial_end; partial_end =3D 0; } + if (head !=3D page) { + unsigned int diff =3D start - 1 - head->index; + partial_start +=3D diff << PAGE_SHIFT; + top +=3D diff << PAGE_SHIFT; + page =3D head; + } zero_user_segment(page, partial_start, top); set_page_dirty(page); unlock_page(page); diff --git a/mm/truncate.c b/mm/truncate.c index dd9ebc1da356..152974888124 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -374,12 +374,19 @@ void truncate_inode_pages_range(struct address_spac= e *mapping, if (partial_start) { struct page *page =3D find_lock_page(mapping, start - 1); if (page) { + struct page *head =3D thp_head(page); unsigned int top =3D PAGE_SIZE; if (start > end) { /* Truncation within a single page */ top =3D partial_end; partial_end =3D 0; } + if (head !=3D page) { + unsigned int diff =3D start - 1 - head->index; + partial_start +=3D diff << PAGE_SHIFT; + top +=3D diff << PAGE_SHIFT; + page =3D head; + } wait_on_page_writeback(page); zero_user_segment(page, partial_start, top); cleancache_invalidate_page(mapping, page); --=20 2.26.2